1. Field of the Invention
This invention relates to a carrier used to unitize a plurality of containers such as cans or bottles.
2. Description of Prior Art
Container carriers, such as the method and carrier according to this invention, are used to unitize a plurality of containers. Typical containers are bottles, cans and other containers having a sidewall and a chime or raised rib around an upper portion of the container. Much of the prior art in this area, specifically container carriers constructed from polymeric materials, comprises devices that engage the chime or rib around the upper portion of the container. Another style of container carrier is the sidewall-applied carrier wherein the carrier engages the sidewall of the container.
Regardless of the style of container carrier, one challenge in the art is to provide a container carrier that can be used with a variety of containers, including different container diameters and containers having sidewalls with different qualities. Specifically, some containers may include sidewalls that utilize different paints or varnished finishes that may change the coefficient of friction between the container and container engaging portions of the multi-packaging device. Because the container engaging portions of the container carrier are generally elastic, which is governed by the modulus of elasticity or “modulus” of the container carrier, the container carrier relies upon the engagement of a stretched container engaging portion with the container sidewall or chime. Container diameters outside of a narrow range of diameters will either stretch the container engaging portion too much thereby permanently losing elasticity, called “neck-down,” or not stretch the container engaging portion at all, both scenarios resulting in package failure.
In addition, container engaging portions may slide too easily or not enough relative to the sidewall of a container depending upon a coefficient of friction of the sidewall thus resulting in package failure. For example, if too much friction occurs between the container engaging portions of the carrier and the container sidewall, application of the carrier will destroy the integrity of the carrier or result in a misapplied carrier relative to the sidewall. Typically, moisture is added to the container or the carrier to permit free sliding of the carrier relative to the container however recent industry trends disfavor use of moisture or water in the packaging process.
Prior art container carriers are typically constructed from a plastic sheet having a single, homogeneous surface having a single coefficient of friction. Prior art container carriers generally require several different versions or configurations to accommodate different container diameters or a certain sidewall smoothness. For example, a matte finish may be applied to an entire carrier to permit application of the carrier to containers having sidewalls with a high coefficient of friction. A disadvantage of the matte finish is that it results in a generally cloudy or opaque carrier that obscures or shrouds graphics on the containers and/or package. It is therefore desirable to provide a container carrier that can accommodate an increased range of containers without adversely affecting package aesthetics.